1. Field of the Invention
The present invention relates to a medical valve assembly and, more particularly, to a two-piece three-way plastic medical valve assembly.
2. Description of the Prior Art
Disposable plastic valves are used extensively in the medical industry because it guarantees to the patient a product which has never been used and it relieves scarce hospital personnel of cleaning, assembly, and quality control when this can best be done by a manufacturer on a mass production basis. Ideally, the valve must meet exacting requirements such as consistent and uniform function without leakage. It must be made at lowest possible cost. If possible, the valve should be producible from a range of materials suitable to meet the needs of the user; clear plastics for some uses, lowest cost plastics to fill another need, specific plastics compatible for assembly to other equipment to fill still a third need.
Valves presently on the market do not have all of these desirable features. Design and molding specifications limit the range of usable materials and the exacting functional requirements are only achievable at higher than desirable cost.
For example, in valves of the type described herein, there is a core and body tapered so that they can come together to a perfect fit. This fit can only be maintained if the core and body are held tightly for any axial shift will cause the valve to leak. In some valves, there is a mechanical interlock between the core and body which holds the two parts. In other valves, the core is held into the body with a third member, a retaining ring. In order to maintain the core and body positioned as required, very close molding tolerances must be held on diameters and on the axial dimensions of the interlock or retaining ring. This increases cost for when the tolerances are not held as is often the case in high-speed, mass production techniques, the parts must be rejected. The tolerance problem is alleviated partially by making the valve from specific, rigid plastics. The plastics chosen are usually a forced compromise between cost, producibility, and the needs of the user.
A further problem relates to the lubrication of disposable valves. This is an expensive and unsatisfactory manufacturing step. The lubricant is an oil which is usually hand-applied to the core or body immediately before assembly. During subsequent handling and packaging, a small portion of this oil or any excess will run and will often be found on the external male sealing surface (Luer taper). The valve can then not be securely assembled into other equipment creating a significant medical hazard.